The present disclosure relates to a microparticle analysis apparatus for optically detecting a specimen such as microparticles or the like, and more specifically, it relates to a microparticle analysis apparatus for detecting multiple light beams regarding one specimen.
In general, in the event of identifying microparticles relating to living bodies such as cells, microorganisms, and liposomes, an optical measurement method using a flow cytometry (flow cytometer) has been employed (e.g., see “Cell Engineering additional volume Experimental Protocol Series Flow Cytometry with Freedom” edited by Hiromitsu Nakauchi, second edition, Shujunsha Co. Ltd. issued on Aug. 31, 2006). This method is a method for identifying multiple microparticles one at a time by a flow cytometry irradiating a laser beam with a particular wavelength on microparticles which make up a row and flow within a flow channel to detect fluorescence or scattered light emitted from the microparticles.
Specifically, a laminar flow is formed of a sample liquid including a microparticle to be measured, and a sheath (capsule) liquid flowing around thereof within a flow channel, and multiple microparticles included in the sample liquid are arrayed in one row. Upon a laser beam being irradiated toward the flow channel in this state, the microparticles passes through the laser beam one at a time so as to traverse the laser beam. At this time, fluorescence and/or scattered light emitted from the microparticles excited by the laser beam is detected by using a photodetector such as a CCD (Charge Coupled Device; charge-coupled device) or PMT (Photo-Multiplier Tube; photomultiplier tube) or the like. The light detected at the photodetector is digitized by being converted into an electric signal, and subjected to statistical analysis, thereby determining the type, size, configuration, and so forth of each of the microp articles.
On the other hand, flow cytometry may detect multiple light beams of which the wavelengths and traveling directions differ regarding one specimen using multiple photodetectors. In such a case, it is difficult to simultaneously detect all of the multiple light beams emitted from the one specimen, and time lag (ΔT) occurs regarding detection of data. However, unless data to be detected at the second and thereafter is confirmed, determination regarding whether or not data detected regarding specimen thereof is pertinent may not be performed.
Therefore, the flow cytometer stores, until all of the light beams are detected regarding each specimen, the data of light detected before the specimen thereof. All of the stored data are read out regarding a specimen determined to be pertinent, and lag of detection time thereof is adjusted, and then processing such as the height of a pulse, calculation of an area, or the like is performed. Also, with a flow cytometer according to the related art, RAM (Random Access Memory) has been used for storage of detected data (see Japanese Unexamined Patent Application Publication (Translation of PCT Application) Nos. 2010-515055 and 2011-503551), and particularly, SRAM (Static Random Access Memory) has been employed.